Lasrick writes: Earlier this month, the US National Nuclear Security Administration (NNSA) announced that it had conducted a subcritical experiment with plutonium in an underground tunnel 300 meters below the Nevada National Security Site (formerly, the Nevada Test Site), about 65 miles northwest of Las Vegas. The Bulletin's first installment in this new series explains what the tests were and whether the government provided the transparency it seeks from Russia and China on similar testing. The series is sort of a Bill Nye for adults.